So Taresian women reproduce by infecting alien males with a retrovirus that rewrites their DNA, effectively turning them ino Taresian males. The women then mate with them, a process that kills the male and presumably impregnates the woman.

So... why don't the Taresians have males of their own, exactly? Presume they give birth to an (almost) equal mix of males and females, just like we do. So wouldn't the natural pattern be that a male grows to adulthood, impregnates a female, and then he dies whilst she goes on to give birth to more males and females for the next generation? If so, why would then need outside males at all?

Or do they only give birth to females, thus having to capture and convert the males of other species to use in their reproduction, kind of like how a parasite uses a host? Only if that's so, how did such a form of reproduction evolve, exactly? Taresians must have evolved long before they developed space travel, right? So how does a species evolve to need alien males for reproduction, when there are no alien males to be had?

Factoid :

In the original script, Kim would have turned out actually be an alien. Garret Wang was excited at the idea of playing "alien Kim" for the rest of the series.

The Nasari ships are a reuse of the Romulan scout ship from Next Generation's "The Defector".

Producer Jeri Taylor is on record of regarding this as one of the weaker episodes of the season. She's not wrong!

Plotline

After Kim fires on an alien ship without orders or warning, he begins to exhibit some unusual genetic changes. Subsequently, Voyagers crew are informed that Harry is really an alien from the Delta Quadrant.